I have an Ice Castle that is fairly new with a forced air furnace. Problem is that the furnace doesn't always kick on. I can hear a faint whine and when I bump the furnace with my fist it kicks on. Also turing the thermostat on and then off again will usually get it to go. Any ideas?

I have had issues with the one in my camper. I took the wires off the furnace and cleaned them. It has not acted up again, htat was a couple of years ago.

could be a bad gas valve, or like eyemaster said check your wire connections. It should go through a process before it ignites. It should run for a few seconds(purge) when you first turn on the t-stat. And then after it does that the ignitor should start clicking.

Like JumoStart73 said...check all connections for tight/broken wire. The fact that when you "bonk" it makes it work sounds like a loose wire, but....you said it "whines'..sounds like the fan is purging the air out, but your gas valve or thermocouple is not "kicking in", allowing the gas to enter, followed by the ignitor kicking in. I'd have this checked by a pro...you don't want to fool around with this, it's just not worth it to take a chance with safety issues on the ice.

Whoops! Should check my spelling, Jumpstart73! Duh...

there is also a sail fin on alot of them fan gets up to speed and moves the sailfin thus opening the gas it might be sticking based on a hitting it and 2 repeated on and off of the thermostate causing a surge to fan maybe knocking it loose

When I hit the furnace the fan kicks on and then shortly after the furnace ignites and then runs fine. I will check the wires as soon as I get a chance.